The present perfect tense is formed using the present tense of the auxiliary verb "have" and the past participle of the main verb. It is used to express actions that started in the past and have relevance in the present. Examples of the present perfect tense include "I have seen ET", "You have eaten mine", and "She has not been to Rome". The auxiliary verb and subject are often contracted in spoken English, such as "I've" and "she's".

1. PRESENT PERFECT TENSES<br />The structure of the present perfect tense is:<br />subject+auxiliary verb+main verb have past participle<br />Here are some examples of the present perfect tense:<br /> subjectauxiliary verb main verb +Ihave seenET.+Youhave eatenmine.-Shehasnotbeento Rome.-Wehavenotplayedfootball.?Haveyou finished? ?Havethey doneit?<br />Contractions with the present perfect tense<br />When we use the present perfect tense in speaking, we usually contract the subject and auxiliary verb. We also sometimes do this when we write.<br />He's or he's??? Be careful! The 's contraction is used for the auxiliary verbs have and be. For example, quot;
It's eatenquot;
can mean: It has eaten. [present perfect tense, active voice]It is eaten. [present tense, passive voice]It is usually clear from the context.<br /> <br />I haveI'veYou haveYou'veHe hasShe hasIt hasJohn hasThe car hasHe'sShe'sIt'sJohn'sThe car'sWe haveWe'veThey haveThey've<br />Here are some examples:<br />I've finished my work.<br />John's seen ET.<br />They've gone home.<br />